Differential mechanism.



Patented Jan. 10, 1,911.

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G. H. GRAHAM.v DIFFERENTIAL MECHANISM.

A PP]Z\ICIA.'..`I0H FILED AUG. 24, 1910. 9815,259o

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Gr.11. GRAEM. DIFFERENTIAL MEGHANISM. APPLIOATIFILED AUG. 24, 1910. 981,259, Patented Jan 10,1911

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@sorge/J1? G. H. GRAHAM.

' DIFFERENTIAL MEGHANI'SM.

APPLICATION FILED AUG. 24, 1910.

Patented Jan. 10, 1911.

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GEORGE H. GRAHAM, O`F` CHICAGO,Y ILLINOIS,- ASSIG-Ill.` 0F ONE-HALF TO FRANK l 7 M'ABSHALILEWIS, CTE" CHICAGO', ILLINOIS.

DIFFERENTIAL MEGHNISM.

Specification of Letters Patent. Patented Jani. 10, 1911.

Application filed August 24, 1910. Serial No. 578,675.

vTo allfwiom it concern.'

Be it known that,y I, GEORGE H. GRAHAM, a citizen of the United States, residing at Chicago, in the county of Cook and State of lllinois,have invented certain new and useful Improvements in Differential Mechanism, of which the following is a specification.

My invention relates to improvements in differential mechanism for self-propelled vehicles and the primary object of my improvement is a construction -whereby power is taken by the driving wheel. offering the great resistancel to rotation, and the consequent distribution of tractive efl'ort acwheel.

A further objectof my improvement is to obviate theobjections to differential mechanisin extant. Chief among such objections is the tendency of the easier turning wheel to absorb the power. (It is well known that however great ther'road friction on.v

say, the'nearside wheel of the car which has its offside wheel on a slippery surface, the power will run to waste, as it were, in uselessly turning/the offside wheel without, maybe, lmoving the carat all.)

A still further object of my improvement is to produce asimple, strong and compact device of the class which will operate with a minimum of friction and can be provided at a comparatively low initial cost.

An important object of my invention is a construction which will permit the driving wheell describing the longer radius curve (when the VehicleV is turning or swerving from a direct path) to revolve independently of the other wheel and at u greater speed and at same time maintaining a'rolling contact of its tire with the road surface.

' lVitli the above and other objects in view, my invention consists in the novel features and in the novel Acombination and arrange 'ment lof parts hereinafter fullyv described,

illustrated in the. accompanying drawings forming. a part of this specification, and particularly pointed out in the claims hereunto appended, it` being understood that changes, variations and modifications in the free ends and details of the invention within' the scope of the claims, may be resorted-to without departing from the spirit or sacrificing any of the advantages thereof.

In the drawings, Figure 1 is'a vertical sectional view of my invention assembled in operative relation of parts.. Fig. '2 is a sectional View on line 2-2 of Fig. 1. Fig. 3 is a sectional view on line 33 of Fig. l. Fig. 4 is a perspective view of-the carrier. Fig. 5is a perspective view of the pinionsector shaft and cam. Fig. 6 is 'a cross section on line GMG in Fig. l. Fig. 7 is a sectional view of a modified form of driving case.

One embodiment of my invention is gen-v erally described as follows: The mecha- -nisin consists of two clutches, one for each wheel, each being comprised of a` clutch wheel-driving vshaft is attached; an internale'xpandino' clutch-shoe having-adjacent operatively related to: a carrier, which is free to rotate on the reduced portion of the driving shaft, and which carries a Apinion-sector meshing with the internally toothed gear or a gear-sector ring forming a central portion of the driving case.

More particularly described, the invention consists of the following:

Referring to the drawings by reference numerals, 8 denotes a single ring having two sectors of gear teeth, 9, at diametrieally opposite points on its inner surface inter-- mediate the ends of the ring which is located in the center of the differential casing, 10, to which isA fixed the 'crown bevel wheel, 11.` The internal gear-sector-ring and the bevel wheel 'are to be considered as a unit, fdithey are solidly bolted together,

and have no movement relative to one an-T other.

Two clutch-drums, 12, 12, are rotatably mounted in and concentric with the inclosing case, 10, and' open toward 'the gear sector teeth and are positioned von either side thereof. The drums are secured to squared ends 13, 13, ofthe driving shafts, 14, 14. Inside these drums are disposed two'internally expanding clutch shoes, 15, 15,01e

4drum to which the squared port-ion of the wheel, 3Q, and internal gear or vslightly less diameter than the drums and having adjacent free ends. The clutches are actuated by two double-actin cams, 16, 16, made solid by squared spind es, 17, 17, with two small pinion-sectors, 18, 18, which latter engage with the gear sector teeth of the respective rings. These cams and pinion-sectors are mounted on and are free to revolve in two carriers, 19, 19, which in their turn have bearing on the reduced round portions, 20, 20, of the drive shaft, and are rotatable thereon. The pinion-sectors are in the same vertical plane. I

Each carrier has a leg, 21, projecting radially from its hub, and each carrier is provided with jaws 22, 22, which support the pinions and cam, the latter, as shown in the drawings, being so placed that its partial rotation tends to open one of the clutchshoes.

The radially projecting leg on each carrier performs no function excepting as a support when assembling the parts to prevent the carrier dropping out ot proper almement. v

The lugs, 253, 23, are spaced apart sutli ciently to receive the free end of theleg, but not to limit oscillatory movement of the leg.

Each carrier has a segmental extension, Q11-, of its hub which construction atlords interlocking hubs that permit a limited movement with respect to each other and both carriers travel in the same vertical plane.

The driving' case has removable ends, QT, 25, with concentric hubs, 26, 26, res] ectivel,v, and the gear-sectoi'aing, S, on the outside of which is secured a gear shown) adapted to receive and transmit power to the motor vehicle through pinion, 27, or chain, as the case may be.

The free end, 28, 52S, of each clutch-shoe has thickened parallel abutments, 29, 29, against which the cam operates to expand the shoe into frictional adherence to the drum. The nume al 30, denotes a reinforcing web to strengthen the ends of the shoe.

.ln Fig. 7, is showna modified form of differential or driving case in which the drivingring, 31, carries any' external. `gear gear sectors, 33, on its inner surface. The gear ring is positioned between the inner ilanged ends, 34, 34, of the case, which are secured together by bolts,

In operation, normally, when the gear is at rest, the clutch shoes are by gravity in contact with a small portion of the inner sur'lace of the drums but upon power being applied to the bevel wheel (or sprocket not shown) the internal gear sector ring begins to revolve solid with the bevel gear and partially rotates the two pinion-sectors. Thus the cams are also partially rotated and expand their respective clutch shoes in the (or sprocket not .sector teeth carried by drums until the grip is so tight that further expansion is impossible. At this point, however, rotation of the cams and the pinion-sector ceases, andthe whole mechanism, including the rear Wheels, rotates as a unit, and moves the vehicle. Y

When the vehicle deviates from a straight forward path or enters a curve, the driving wheel descri hing the longer radius curve automatically releases from the source of power and freely revolves independently of' the other wheel, at an increased speed, and at the same time, maintains a rolling contact of itstire with the road surface. The automatic release is accomplished by the driving wheel describing the longer radius ein-ve rotating' faster and its clutch-drum causes the carrier to advance in relation to the gear-toothcd-sector, thus moving the axis ot' the pinion-sector forward in respect to the gear-sector, and reversing the action which resulted in setting the cam, whereby the clutch shoe is released and the outer traction wheel is free to revolve at a greater speed than the inner traction wheel.

lla ving thus :tul'ly described my invention, what l claim as new, and desire to secure by Letters-Patent, is

1. ln a dilterential mechanism the combination of a shaft, a clutch-drum fixed thereto, a clutch-shoe having adjacent free ends, a pinion-sector, a carrier for the pinion` sector, a ringhaving a sector ol' gear teeth at dialnctrirally opposite points on its inner .surface and meshing with the pinion-sector, and cam .means operatively connected With the pinion-sector to expand and release the clutch-shoe. i

Q. ln a dill'erential mechanism, the combination ot a shaft, .a clutch-drum fixed thereto, a clutch-shoe, a pinion-sector, a carrier for the pinion-sector, a driving case, gearthe case and meshing willi the pinion-sector, and means operatively connected with the pinion-sector to expand and release the clutch shoe.

23. In a ditlerential mechanism, the combination ot' independent shafts, a clutch-drum fixed to one end oi each shaft, a clutch-shoe having adjacent free ends and disposed within each drum, means disposed in the same vertical plane, and comprising a pinion-sector iixcd to a shaft having a double acting cam positioned between the free ends ot. each clutch-shoe to expand and release the same, a carrier for each pinion-sector, a driving case having inwardly extending gear teeth i'ncshing with the respective pinion-sectors, and means carried by the driving case adapted to receive power to rotate such driving case.

ft. In a differential mechanism, the com` bination with a driving-shaft and drivingwheel of a self-propelled vehicle, of a clutchshoe having adjaeent free ends, a carrier-ro. tatable on the shaft, and means comprisin a pinion-sector -iixed to an independent sha t with one end having a cam posivioned oet-ween the free ends of the elutcli-shoe to expand and release the same.

In a differential mechanism, the combir nation or a driving-case, ineens fixed to the exterior of the case to receive power to rotate suoli ense, a portion of the driving ease having on its inner surface inwardly extending gear teeth, a pinionesector mounted upon n shaft with one end in the form of a cani, a carrier rotatably ion-sector and a clutch consisting of a r' rum and an internal expanding shoe having adjacentv free ends. 6. In a differential mechanism, the combination with :1, driving shaft and driving wheel of a self-propelled vehicle, of a clutch consisting-of' a drum and an internal expanding shochaving adjacent free ends, a pinieirseetor, a rotatably mounted carrier supporting the pin# Sie for the pinion-sector, n driving caseliaving inwardly extending gear teeth meshing with the pinion-sectorn nieans operatively connected with the pinion-sector to actuate the shoe, and menne carried by the driving case adapted to receive power to rotate the case.

7. In a diliereniial mechanism, the combinationof independent shafts, clutch means disposed in operative relation at the inner end oi each shaft, a plurality of pinion-sectors in the Same vertical plane and carrying means. to operfiietl'ie respective elntelinieans, a pluralily of carriers rotatably mounted and traveling in the saine vertical plane and supporting tlie iespeeli ve pinion-sectors,

and means to impart motion to tlie pinion' sectors.

In testimonyY whereof, l aliix niy signature in the presence of two witnesses.

GEORGE H. GRAHAM.

`Witnesses S. ELVA Knnioee,

JOHN W. Kivnm. 

